The well-received sequel to the lovable game Portal has now topped four million units sold on PC, Mac and consoles. Coincidentally, the release of Portal 2‘s new Perpetual Testing Initiative DLC falls on the same day as the sales news. To mark the new DLC, Steam has made the Portal series one of its midweek madness sales. You may now purchase Portal 2 and receive the new DLC for free with your order for just $6.79 (66% off). Additionally, you may purchase the original game 66% off as well at $3.39 or you could buy the bundle which includes Portal and Portal 2 for just $8.49.

Perpetual Testing Initiative DLC trailer

In addition to the Portal series being on sale, Alan Wake is also on sale on Steam for its midweek madness. Alan Wake is on sale for 50% off $24.99, thus making it $14.99. The Alan Wake Collector’s Edition is also available for $17.49 which includes the original game plus the full soundtrack, developer commentary videos, and 130 page illustrated PDF book or if you have the game and want the extras, they are $4.99 standalone. To add to the sales news, you may now pre-order Remedy Entertainment’s Alan Wake’s American Nightmare on Steam which is available on May 22nd.You may also pre-purchase the game from Good Old Games.